Backpacks or knapsacks have been in use for many years. Such devices typically comprise a central storage compartment and optional secondary storage compartments. Attached to the central storage compartment is generally two straps which are worn about the shoulders of the user so that the backpack is partially supported by the shoulders and the back of the user.
Backpacks of the type disclosed in U.S. Pat. Nos. 432,607; 5,129,560; 5,431,317; and 5,577,652 are generally stiff shaped or non-flexible backpacks. Such backpacks typically have closures such as zippers. Such non-flexible backpacks are not comfortable because they have stiff edges which apply pressure to various portions of the user's back, and are awkward to carry. In addition, such backpacks can not be condensed so that they can be easily stored within a suitcase and transported during travel.
Another disadvantage of conventional backpacks whether having a zipper or drawstring closure is that entry to the central storage section is typically exposed to the public when the user is wearing the backpack. The closure is rather an easy target for someone who wishes to gain entry into the backpack even when the backpack is worn by the user.
It is therefore desirable in the backpack industry to provide a backpack assembly which is flexible, more comfortable to wear, allows for storage of materials in a flat condition and provides greater security than conventional backpacks described above. It would therefore be an advance in the art of developing backpacks to provide a backpack which provides a surface in contact with the back of the user which is generally flexible, conforms to the contour of the user's back, yet can carry flat materials in an unfolded condition. It would be a further advance in the backpack art to provide a backpack having a closure system which can not be readily tampered with when the user is wearing the backpack.